Scribe May 14

The day started off as usual, with a POD. Mr Alcantara told us that it was taken from the 11A blog.

It went like this:

Antonio went to the doctor. For his growth, the doctor recommended that he should drink three glasses of milk each day, and each day drink half more than the last day. Find the total amount of glasses he drank by 2 months. Assume each month has 30 days.

After everyone worked on it individually, Jaime came up to the board and solved it.

Jaime's work:

First, he found T60 by using the arithmetic sequence equation.

Tn = T1 + (n - 1)d

3, 3.5, 4

3.5
- 3
.5

T1= 3
D: .5


T60 = 3 + (60-1)(.5)
T60 = 3 + (59)(.5)
T60 = 32.5

Then, he used the arithmetic series formula to find the sum of glasses Antonio drank for 2 months (or 60 days).

Sn = n x ( T1 + Tn)
2
S60 = 60 x ( T1 + T60)
2
S60= 60 x ( 3 + 32.5)
2
S60 = 30 x ( 35.5)
S60 = 1065 glasses of milk

After solving the POD, Mr Alcantara showed us three more problems from the 11A blog. We spent the rest of the class solving them.

Problem 1
Susana goes to the store and buys one chocolate bar. She ate it and loved it so much that she went back to the store and bought 4 chocolate bars. Then, she went back to the store and bought 16 chocolate bars. If she went 16 times to the store, how many chocolate bars did she buy?

First of all, before solving the problem we have to take into consideration the following question:
What kind of problem is this?

Alejandro went to the board to solve the question. He explained that we had to use the equation for geometric series in order to find the sum of the first n terms.

His work went out like this:
Term: 1 2 3
1 4 16
rate: x4 x4

Sn = T1 x 1 -r^n
1-r
S16 = 1x 1 -4^16
1-4
S16 = 1 x (1,431,655,765)
S16 = 1,431,655,765

Problem 2
Colegio Jorge Washington accepts 8 new students for each class every year. If a class begins with 15 students in prekinder, how many students will there be when that class is in 7th grade?

This question is an arithmetic sequence problem, therefore Isabella wrote in the board:

Tn = T1 + (n - 1) d

Prekinder, Kinder, 1st, 2nd, 3rd, 4th, 5th, 6th, 7th grade
15 15 23 39
+ 8 8 8
23 + 8 8
39 + 8
63


T9 = 15 + (9 - 1) (8)
T9 = 15 + (8)(8)
T 9= 15 + 64
T9 = 79 students

Mr Alcantara then asked us to re-word the question in order to make it an arithmetic series problem. This was a challenge for the class, since everything we tried seemed to end up being an arithmetic sequence problem. There were some suggestions:

Colegio Jorge Washington accepts 8 new students for each class every year. If a class begins with 15 students in prekinder,

Melissa's: What is the population of Cojowa from Pre-kinder to the 7th grade?

Kris's: How many new students are there from Pre-kinder to 7th grade?

Mr A's: Colegio Jorge Washington accepts 8 new students more than they accepted the year before for each class. If a class begins with 15 students in prekinder, how many students will there be in 7th grade?

This problem became stressful for the class, so we just decided to go on the next one.

Problem 3
Sandra bought three dogs in the store. She was a dog addict and had to have more and more dogs each week. The next week she had 9 dogs in her house. After two weeks, her neighbor found 27 dogs. Find out how many dogs she had after 27 weeks.

Term: 1 2 3
3 9 27
Ratio: x3 x3

This is a geometric sequence.Therefore, we use the formula of a geometric sequence to find the nth term.

Tn = T1 x r^(n - 1)
T27= 3 x 3^(27-1)
T27=3 x 3^(26)
T27= 7.625597485 x 10^5

This was everything we did today in class. Today's homework is to edit your word questions by midnight. Remember to include the names of everyone in your group.

We ended class with Mr Alcantara telling us the story of Sybil the rat, but the bell rang, so he said he would post the question in the blog so anyone who had time would solve it.

THE SCRIBE FOR TOMORROW IS MELISSA COVO.